1. Field of the Invention
The present invention relates in general to a horizontal type rotary compressor for use in a refrigerating system and, more particularly, to an oil delivery prevention device for the compressor for separation of mixed gas into refrigerant gas and oil and for prevention of oil from delivery along with the refrigerant gas to a refrigerating cycle.
2. Description of the Prior Art
With reference to FIG. 1, there is shown a conventional horizontal type rotary compressor. As shown in this drawing, a compressor casing 1 receives a drive unit D and a compressing unit C which are cooperate with each other through a horizontally placed rotating shaft 6. Oil is received in an oil reservoir of the lower section inside the casing 1.
The drive unit D comprises a stator 12 fixed to an inner surface of the casing 1 and a rotor 11 fixed to the rotating shaft 6. The compressing unit C includes a cylinder 2 which is hermetically covered with a main bearing 4 and a sub-bearing 3 at its opposed ends. The main and sub-bearings 4 and 3 defines a compressing chamber 5 in the cylinder 2.
In the compressing chamber 5 of the compressing unit C, an eccentric part 7 of the rotating shaft 6 axially extends and a roller 8 is fitted over the eccentric part 7. The roller 8 as well as the eccentric part 7 rotates in the compressing chamber 5 as a result of rotation of the rotating shaft 6. The Cylinder 2 of the compressing unit C is provided with a radial slot receiving a radially reciprocating blade 9b. This reciprocating blade 9b is biased by a compression coil spring 9d at its lower end and always elastically contacts with the outer surface of the eccentrically rotating roller 8 of the eccentric part 7 at its distal end. A blade chamber 9c is defined below the blade 9b and an ON/OFF valve 9e is provided at the bottom of the blade chamber 9c. Connected to a side wall of the blade chamber 9c is an oil feed pipe 9a for suction and delivery of the oil O and introduction of the oil O to a shaft bearing 6a of the compressing unit C. This oil feed pipe 9a is connected to the side wall of the blade chamber 9c and a center of the shaft bearing 6a at its opposed ends so that the shaft bearing 6a communicates with the blade chamber 9c through the pipe 9a.
In the above horizontal type rotary compressor, an oil delivery prevention device 10 is provided at the right side of the drive unit D as shown in FIG. 2 and adapted to separate a mixed gas into the refrigerant gas and the oil and to prevent the oil from delivery along with the refrigerant gas to a refrigerating cycle. The oil delivery prevention device 10 comprises an oil separating disc 15 which is partially provided with a balance weight member 14 at its edge. Formed on the oil separating disc 15 at a position opposed to the balance weight member 14 is an oil delivery port 16.
In operation of the above oil delivery prevention device 10, the rotor 11 and the rotating shaft 6 are rotated upon applying the electric power to the drive unit D. As a result of rotation of the rotating shaft 6, the roller 8 fitted over the eccentric part 7 of the shaft 6 is eccentrically rotated in the compressing chamber 5, thus to achieve a desired compression in the compressing chamber 5.
At the same time of the eccentric rotation of the roller 8, the reciprocating blade 9b contacting with the outer surface of the roller 8 at its distal end radially reciprocates and carries out an oil feeding operation. That is, when the blade 9b radially moves upward as shown by the arrow in FIG. 1 such that it enlarges the volume of the blade chamber 9c, oil is introduced into the blade chamber 9c from the oil reservoir of the lower section of the casing 1.
When the blade 9b radially moves downward in a direction opposed to the arrow direction of FIG. 1 such that it reduces the volume of the blade chamber 9c, the oil in the blade chamber 9c is introduced into the oil feed pipe 9a and thence directed to the shaft bearing 6a.
On the other hand, the refrigerant gas is introduced into the compressing chamber 5 through an intake port 9 and a refrigerant gas conduit 8a. The refrigerant gas in the compressing chamber 5 is compressed and, thereafter, delivered to a muffler 13 through a valve (not shown). The refrigerant gas delivered from the compressing chamber 5 passes through a compressing unit space S.sub.1 in order to be directed to motor inner and outer spaces S.sub.2 and S.sub.3 by the centrifugal force of the rotor 11.
At this time, since the pressurized refrigerant gas is mixed with the oil at a high temperature under a high pressure and becomes a refrigerant gas mixture (hereinafter, referred to simply as "mixed gas"), the mixed gas needs be prevented from directly delivered through a delivery pipe 10a. In order to achieve the above object in the prior art, the oil delivery prevention device 10 is provided at the right side of the drive unit D, that is, at the rear side of the rotating shaft 6. With the oil delivery prevention device 10, the mixed gas whirls and comes out between the rotor 11 and the stator 12 owing to the centrifugal force of the rotor 11 during rotation of the rotor 11. Thereafter, the mixed gas coming out between the rotor 11 and the stator 12 strikes against the oil separating disc 15 vertically placed at the rear side of the rotor 11 and the stator 12. At this time, part of the mixed gas whirls in the motor inner space S.sub.2 and thence delivered from the oil delivery port 16 by way of the motor outer space S.sub.3. The other mixed gas gathers in the motor outer space S.sub.3 through the gap between the oil separating disc 15 and the stator 12. The mixed gas gathering in the motor outer space S.sub.3 is somewhat separated into refrigerant gas and oil and delivered through the delivery pipe 10a. That is, when the mixed gas strikes against the oil separating disc 15, it is separated into refrigerant gas and oil due to the surface tension. The separated oil sticks to the oil separating disc 15 and, thereafter, drops down to the oil reservoir of the casing 1 due to the gravity.
However, the above oil delivery prevention device has a problem that the oil separating disc does not make the most of its intrinsic function. Another problem of the above device is resided in that it can not achieve a desired complete separation of the oil from the mixed gas since part of mixed gas simply passes through the gap between the stator and the oil separating disc, thus to deteriorate efficiency of the associated refrigerating cycle.